Field of the Invention
This disclosure relates to a collected toner container storing a corrected toner.
Description of the Related Art
An image forming apparatus configured to collect and accumulate a developer, an additive agent, paper powder and the like collected from a developing unit, a belt cleaning unit, photoconductive drums and the like into a collected toner container arranged in a housing of the image forming apparatus is widely used. As a result of an attempt made to store the collected toner container compactly in the housing of the image forming apparatus, there is a case where an appearance configuration of the collected toner container may hinder an effective accumulation of the developer in the collected toner container. For example, in order to accumulate the developer so as to be dispersed over the entire part of the collected toner container having an elongated appearance configuration, the developer supplied to an end of the collected toner container needs to be conveyed to the other end.
In a collected toner container of Japanese Patent Laid-Open No. 2009-271276, a screw conveying member is arranged in an inside space of the elongated collected toner container, and delivers the developer to the entire part of the inside space by conveying the developer from both ends to a center of the inside space in association with a rotation of a screw member.
Japanese Patent Laid-Open No. 2013-44884 discloses a screw member configured to convey waste toner from one end to the other end in the collecting container, including screws configured to convey the toner in directions opposite to each other and being arranged alternately on the same axis in order to improve a storage efficiency of the collecting container. In the configuration disclosed in Japanese Patent Laid-Open No. 2013-44884, a first helical screw portion configured to convey the toner in a forward direction, and a second helical screw portion configured to convey the toner in a reverse direction of the screw member are arranged alternately, and the number of turns of the second helical screw portion is constant.
Therefore, there are the following problems. If the number of turns of the reverse conveyance screw is increased in order to improve filling efficiency, the amount of returned toner at a merge portion between a forward conveyance section and a reverse conveyance section is increased, and hence there is a probability that the toner is clogged and spills out on the upstream side of the collecting container in the direction of conveyance. In contrast, if the number of turns of the reverse conveyance screw is reduced uniformly, the following problem may occur. In other words, an amount of filled toner at the merge portion between the forward conveyance section and the reverse conveyance section is disadvantageously reduced as it goes downstream in the direction of conveyance.
The reason is as follows. According to the review of the inventors, the toner is heaped up at the merge portion between the forward conveyance section and the reverse conveyance section. At the merge section, if toner of a predetermined amount is heaped up high at a merge portion, the toner is conveyed toward a next merge section on the downstream side before the former merge section is completely filled up. While the toner is conveyed to the merge portion on the downstream side, filling at the merge portion on the upstream side is still in progress. Therefore, the filling rate at the merge portion on the upstream side tends to be higher than that at the merge portion on the downstream side. Therefore, there is a probability that the filling rate on the downstream side is lowered if the number of turns of the reverse conveyance screw is constant.